Recombinant Human Interferon-β Suppresses the Replication of HIV and Acts Synergistically with AZT

The in vitro effects of recombinant human interferon-β_ser (rIFN-β_ser) and 3′-azido-3′-deoxythymidine (AZT) alone and in combination on human immunodeficiency virus (HIV) replication were examined. rIFN-β_ser inhibited HIV progeny virus synthesis in cell cultures chronically infected with HIV. When used in combination, suboptimally effective concentrations of rIFN- β_ser and AZT synergistically inhibited HIV-mediated syncytium formation in HeLa T4 cell cultures. Whereas AZT alone reduced HIV replication in human MT-2 cells, addition of low concentrations of rIFN-β_ser reduced by 4- to 1,000-fold the amount of AZT required to maximally block HIV p24 antigen synthesis and HIV-mediated cell lysis. No drug-related cytoxicity was observed when the two agents were used together at and above maximally effective concentrations. These results suggest that a safer, yet effective, therapy for HIV infections may be achieved with reduced doses of AZT in combination with rIFN-β_ser.